White balancing is a fundamental step in the image processing pipeline. The process involves estimating the chromaticity of the illuminant source and using the estimate to correct the image to remove any color cast. Given the importance of the problem, there has been much previous work on illuminant estimation. Previous work is either more accurate but slow and complex, or fast and simple but less accurate. In this paper, we propose a method for illuminant estimation that uses (i) fast features known to be predictive in illuminant estimation and (ii) single feature decision boundaries in ensembles of multivariate regression trees, (iii) each of which has been constructed to minimize a multivariate distance measure appropriate for illuminant estimation. The result is an illuminant estimation method that is simultaneously fast, simpler, and more accurate.